Virus Alert on Taskbar...AND MORE!!!

Ok, so I think I have the same problem as alot of others here, so hopefully you can help??

I have Norton2005 and Lavasoft Adaware, but was taken for a sucker when a very clever program installed itself on my PC, posing as a Microsoft program!! I'm really hacked off, but it seems you folks are good with this sort of thing.

I have the constant "Virus Alert" icon in the taskbar, along with a pop-up balloon that keeps telling me to click on it, and also my homepage wont stay at google, where it's supposed to be!!

Thanks very much for the advice. I ended up sorting it with a couple of other bits of software (Smitfraudfix (or something like that!) and ewido). I found a link to a blog which ran through it all and I'm clean and healthy again. Thanks for the help though.